This work addresses the model-based optimization of the operation procedure of a fed-batch emulsification process in a stirred vessel. The computation of the input trajectories (i.e. the stirrer speed and the oil flow addition rate as function in time), for reaching a certain predefined, terminal, drop size distribution (DSD) in minimum time, is studied. It is explained that general optimization techniques do not give satisfactory results for this optimization problem. It is suggested to approximate the original minimum time optimization problem as a Mixed Integer Linear Program (MILP). The MILP can be solved for its global solution, which is a good solution of the original optimization problem. The feasibility of the approach is illustrated by means of several optimization studies. The optimization results indicate that the operation time can be decreased by applying non-conventional input trajectories. (C) 2003 Elsevier Ltd. All rights reserved.